Pipelines are used for delivery of many different fluid types including gasses, water, liquid chemical compositions, liquid foodstuffs, oil and other petroleum based products.
Leakage, fracturing or bursting (referred to as “faults”) of a pipeline can have severe consequences. Such faults will almost always have financial implications to the pipeline operator both in terms of loss of fluid to the environment, cost to repair or replace the pipeline and cost to reach the pipeline to effect the repairs and then make good any damaged caused by the repair. Depending on the fluid and its use, there can also be other direct or indirect implications. Direct implications include environmental damage by the leaking fluid (for a petrochemical or chemical leak can be hazardous) and also safety issues (for example, leaking natural gas has an associated risk of explosion and/or ignition). Indirect implications are often concerned with loss of service provided by the pipeline and the impact of the loss of service to the served customers or systems.
One area where faults are relatively commonplace in pipelines is in water supply pipelines. Drinking water is commonly supplied under pressure via what is referred to as a water distribution main. Drinking water distribution networks commonly have a loop or branch network topology, or a combination of both, supplied by so-called “trunk mains”. The piping networks are often circular or rectangular. If any one section of water distribution main fails or needs repair, that section can be isolated without disrupting all users on the network.
A catastrophic trunk main failure is capable of causing both immense damage and dislocation to the day to day operation of a water supply network. Alongside that, however, has to be balanced the risk of such an event occurring and the cost of mitigating the risks of such an event occurring.
As water mains are typically buried below ground, accessing them is complicated, expensive and disruptive. As a result, many utility companies operate reactively (fixing faults as they arise) rather than pro-actively replacing out-dated pipelines (for example, many of London's drinking water mains are said to date back over 100 years). In addition to the sheer cost of replacement, it is difficult for utility companies to be pro-active when the potential fault is buried and out of sight. It can be some time before a fault is even identified.